geopyv.subset

Module Contents

Classes

Subset

Initialisation of geopyv subset object.

SubsetBase

Subset base class to be used as a mixin. Contains plot functionality.

SubsetResults

Subset results object for geopyv.
class geopyv.subset.Subset(*, f_coord=None, f_img=None, g_img=None, template=None)

Bases: SubsetBase

Initialisation of geopyv subset object.

Parameters:
data

Data object containing all settings and results. See the data structure here.

Type:

dict

solved

Boolean to indicate if the subset has been solved.

Type:

bool

solve(*, max_norm=0.001, max_iterations=15, order=1, p_0=None, tolerance=0.7, method='ICGN')

Method to solve for the subset displacements using the various methods.

Parameters:

  • max_norm (float, optional) – Exit criterion for norm of increment in warp function. Defaults to value of \(1 \cdot 10^{-3}\).

  • max_iterations (int, optional) – Exit criterion for number of Gauss-Newton iterations. Defaults to value of 50.

  • order (int) – Warp function order. Options are 1 and 2.

  • p_0 (ndarray, optional) – 1D array of warp function parameters with float type.

  • tolerance (float, optional) – Correlation coefficient tolerance. Defaults to a value of 0.7.

  • method (str) – Solution method. Options are FAGN and ICGN. Default is ICGN since it is faster.

Returns:

solved – Boolean to indicate if the subset instance has been solved.

Return type:

bool

Note

  • The warp function parameter array can be used to precondition the computation if passed non-zero values.

  • Otherwise, the initial guess at the subset displacement is performed by _get_initial_guess().

  • If not specified, the solver defaults to a first order warp function.

  • For guidance on how to use this class see the subset tutorial.

See also

_get_initial_guess_size() _get_initial_guess()

class geopyv.subset.SubsetBase

Subset base class to be used as a mixin. Contains plot functionality.

convergence(show=True, block=True, save=None)

Method to plot the rate of convergence for the subset using convergence_subset.

Parameters:

  • show (bool, optional) – Control whether the plot is displayed.

  • block (bool, optional) – Control whether the plot blocks execution until closed.

  • save (str, optional) – Name to use to save plot. Uses default extension of .png.

Returns:

  • fig (matplotlib.pyplot.figure) – Figure object.

  • ax (matplotlib.pyplot.axes) – Axes object.

Note

  • The figure and axes objects can be returned allowing standard matplotlib functionality to be used to augment the plot generated. See the plots tutorial for guidance.

Warning

  • Can only be used once the subset has been solved using the solve() method.

See also

convergence_subset()

inspect(show=True, block=True, save=None)

Method to show the subset and associated quality metrics using inspect_subset.

Parameters:

  • show (bool, optional) – Control whether the plot is displayed.

  • block (bool, optional) – Control whether the plot blocks execution until closed.

  • save (str, optional) – Name to use to save plot. Uses default extension of .png.

Returns:

  • fig (matplotlib.pyplot.figure) – Figure object.

  • ax (matplotlib.pyplot.axes) – Axes object.

Note

  • The figure and axes objects can be returned allowing standard matplotlib functionality to be used to augment the plot generated. See the plots tutorial for guidance.

See also

inspect_subset()

class geopyv.subset.SubsetResults(data)

Bases: SubsetBase

Subset results object for geopyv.

Parameters:

data (dict) – geopyv data dict from Subset object.

data

geopyv data dict from Subset object.

Type:

dict

Note

  • Contains all of the plot functionality provied by SubsetBase but none of the algorithms provided by Subset (i.e. you can’t use this to re-analyse images). Purely used to store data and interrogate results.

Warning

  • To re-analyse data instantiate a new object using Subset and use the solve method.